The present invention relates to the field of computer telephony in general and to policing call requests arising in computer telephony networks.
The control of unauthorised calls made from phones in a corporate phone system, such as a company phone system comprising a number of phones has long been seen as a problem. In a corporate environment, unauthorised phone calls constitute a number of risks. This can be from a number of perspectives:                cost (i.e. accessing high charge-rate destinations: international, premium rate);        time (i.e. working time spent on unauthorised, personal calls);        regulation/compliance (i.e. unauthorised phone calls breaching industry regulations).        
Typically, phone systems have the ability to bar calls originating from both an individual phone and a group of phones. An inherent weakness in such systems is that an individual assigned a phone to which call barring is applied may go around the organisation trying different phones, until one is found that allows the desired type of call.
To address this weakness, some PBX vendors have introduced a concept whereby a, use can “register” on a phone of their choosing using a unique, confidential code (PIN). On registering, the phone effectively becomes theirs, i.e. it takes on their extension number and is assigned their personal settings, including their call barring status.
This is only a partial solution to the problem. User registration can be effective in a small organisation whereby all the users share one, suitably-equipped PBX. However, in large organisations, there will be typically many PBXs, often from different manufacturers and in different versions, rendering the registering of any phone unworkable.
Another potential solution would be to set up an automated bureau service whereby individuals dial a particular number, identify themselves using a PIN, key in the number they wish to dial and, if this is an authorised number for use by that user, the service will then place the call on their behalf.
Although effective, this is clearly a tedious way of making calls and has very significant drawbacks where calls are often made in an automated fashion (e.g. from the user's PC using a computer-telephony client and a directory of contacts or Instant Messaging client application such as OC (Office Communicator from Microsoft). In a conventional CTI system, a user can use their computer terminal to request an outgoing call to be set up from a telephony terminal registered in association with the user's computer terminal. A CTI controller responds to the computer-originated request by commanding a PBX that serves the user's environment to set up a call from the appropriate telephony terminal. These automated call systems will obviously not work if the phone associated with the client defaults to a state in which some calls (e.g. all chargeable calls) are barred requiring the user to enter their security details manually to a bureau service.
Current practices for call barring in a computer telephony environment are inadequate and problematic and there is a need for a method of allowing call barring based on an individual's permissions in automated dialling environments.
A system and corresponding method are proposed for policing call requests originating in a computer telephony (CTI) system, in which the computer telephony system comprises a plurality of computer terminals and a plurality of telephone terminals. The system for policing call requests comprises a store for storing a set of permissions associated with a user; and for storing a registration associating a computer terminal with a source telephone terminal. The system also comprises a CTI server for receiving from the user via the computer terminal a request to set up a call from the source telephone terminal to a destination telephone terminal. The call set-up request comprises a user identifier associated in the store with the set of permissions. The CTI server is arranged in use to compare the call set-up request with the set of permissions; and to allow or block the call depending on the permissions.
The method includes receiving at a CTI server from the user via one of the computer terminals a request to set up a call to a destination telephone terminal; in which the request identifies the user. The CTI server compares the call set-up request with the set of permissions associated with the user; and allows or blocks the call depending on the permissions.
According to a further aspect, the call request is associated with a source telephone terminal and a number identifying the destination telephone terminal; in which the source telephone terminal is an extension to a PBX, in which the CTI server forwards an allowed call request to the PBX. According to this further aspect, the PBX comprises call barring settings relating to the source telephone terminal, in which the CTI server overrides the PBX call barring settings.
According to a further aspect, the CTI server directs the PBX to route the requested call via a second PBX. According to a further aspect, the second PBX allows or blocks the call depending on the result of a comparison of the call set-up request with the set of permissions associated with the user. According to a further aspect, the second PBX allows or blocks the call depending on the result of checking call validation data provided by the CTI server.